In November 2012, the first TVs with 4K resolution went on sale in the United States. The very first was the LG 84EM9600, but hot on its heels came this Sony XBR-84X900.

As of early 2013, they're still the only 4K TVs you can buy. If you have the money. And you probably don't. The list price is $20,000 for the LG and $25,000 for the Sony.

Both TVs are 84 inches diagonal and equipped with what Sony admits are the same panel (made by LG) and similar backlight technology, namely edge-lit with local dimming. For the extra cash Sony throws in fancier speakers and a free server loaded with a few 4K movies and shorts, but the real selling point of both TVs, if one exists, is the extra resolution of their screens. After all, you can get a 90-inch 1080p Sharp for less than half the price.

As we've explained at length before, however, that extra resolution isn't necessarily visible, let alone worth the extra money. And after spending some quality time with the XBR-84X900, our opinion hasn't changed.

Sony's 84-inch XBR-84X900 4K TV costs $25,000.
Sony

Sony: 'Hands-on, yes; full review, no.'
In late February, three months after its debut, we got our first extended time with the XBR-84X900 -- our first with any 4K TV. The down side? Sony didn't ship it to our lab for a formal review. I had asked for just that, so I could put it through our punishing regimen of tests and compare it with other televisions.

For whatever reason -- maybe it's the punishment, maybe it's our Value rating -- the company said "no." Normally I refuse to evaluate products like this outside of a lab setting, but in the XBR-84X900's case I'm making an exception. I was too curious about 4K, and the company did allow Ty Pendlebury and I a full day with the set, with our own equipment, a mini comparison lineup, and a dark room somewhere upstairs at Sony's Manhattan headquarters.

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What follows isn't a full, rated review, but I tried to make it as meaty as possible under the circumstances. I played with the picture settings and took rudimentary measurements, but I didn't have time for a full calibration, and even if I did, it would have been largely pointless. That's because Sony didn't want me to mention any comparisons with the other two TVs in the lineup (the LG 84EM9600 and a Sharp LC-80LE632U) other than the comparisons that its own engineers had arranged. In addition to showing us a bunch of demos, which unsurprisingly made the XBR-84X900 seem like the best TV in the room, those engineers hung out with us the entire time. Sure it was awkward, and I'd much rather have been back at my own lab, able to give this very special TV an actual CNET review, but at least lunch was good. And meaty.

More importantly, I got a pretty clear picture of the XBR-84X900's picture quality. It appears to be an excellent-performing LCD TV overall, although the benefits of 4K in 2D are vanishingly subtle, when they're visible at all. Size notwithstanding, I'd personally rather watch one of the better plasmas, especially because of the inherent uniformity issues in LCD, but I have little doubt Sony knows how to get some of the best pictures possible out of an edge-lit LED-based LCD TV.

Ty Pendlebury/CNET

How much does 4K improve picture quality?
From what we saw, not much. We can't yet fully answer that question, of course, but in limited experience with the Sony, Ty and I can come closer than we have before. In the demos we were shown and the material we chose to watch ourselves, the benefits of 4K on the XBR-84X900 ranged from extremely subtle to nonexistent to our eyes.

I entered Sony's demonstration room solidly believing that 4K TVs are stupid. At even massive screen sizes like the 84 inches of the XBR-84X900, science says the human eye can't resolve the difference between 1080p and 4K from normal seating distances. Sony knows the math behind TV resolution and seating distance, obviously, because it had set up our two prime viewing seats about 8 feet from the big screens. That's too close for most viewers, and for most of the palatial dens and living rooms of this TV's target audience.

Unfortunately there was no way for me to perform the best test of this kind of math: comparing an 84-inch 4K Sony directly to its closest 1080p equivalent, the 80-inch Sharp, using native 4K material on the former and the same material at 1080p resolution on the latter. Sony's "no outside comparisons" rule, and lack of such content on-hand, prevented it.

...the benefits of 4K in 2D are vanishingly subtle, when they're visible at all.

The engineers did show us what they said was the same 1080p material distributed to all four TVs (for this and all subsequent Sony-sanctioned comparisons, they claimed all four of the TVs were set to their default Cinema or Movie settings). Fine details in a clip we saw of a "Downton Abbey"-style estate, most revealingly of gravel, trees, building facades and the faces of period-dressed perambulators, did seem more detailed on the 4K sets than the Sharp, and between the Sony and the LG I'd give the slight edge to the Sony. However, this was mainly a test of the upconverting and video-processing prowess -- or lack thereof -- of Sony and LG, and I don't know whether the Sharp was as well adjusted as it could be. In short, this cross-brand resolution comparison was severely compromised.

The resolution demo I trusted the most involved both of the Sony XBR-84X900s in the lineup, which the engineers told us were identical. One showed a clip of uncompressed 4K video, and the other was showing the same video compressed down to 1080p. It was difficult to tell the difference between the two, even when we walked right up to the screen. The 1080p video did look a bit less detailed in the very highest-resolution areas -- for example, bricks on a still shot of a courtyard, or people in a town square seen from high above -- but we had to look closely from a seating distance of about 6 feet, and real differences emerged only from very close.

...we had to look closely from a seating distance of about 6 feet, and real differences emerged only from very close.

One demo, of high-resolution digital still photos, showed a big resolution difference between the LG and the Sony. I wondered whether something was amiss with the very soft-looking LG, and Sony's engineer hypothesized that it probably has a "buffer issue," causing it to truncate the resolution of digital photos from USB (and presumably other sources, like DLNA). Whatever the reason, still photos in Sony's demo looked much better on the Sony TV.

Sony includes an Xperia Tablet S with every 84-inch 4K TV, complete with an app for navigating the included server-full of 4K video.
Ty Pendlebury/CNET

The importance of video processing
As Sony's reps pointed out to us repeatedly, it all comes down to video processing. That's because, for the moment, 4K content is very scarce (although Sony gets extra credit for addressing that dearth -- more below), so the TV has to upconvert all that 1080p content for the 4K big screen. Sony harps on its 4K Reality Creation engine as superior to the competition, but since I couldn't compare it with LG's myself, I just don't know.

I did play around with the settings on the XBR-84X900, and the difference between Off, Auto, and Manual was readily apparent from my close-up seat, albeit less so as I moved farther back. I typically leave such processing off with 1080p TVs I review since it often adds edge enhancement or other undesirable effects, and my main goal in adjusting a TV is to present the content as close to the director's intent as possible.

With a 4K TV I might be tempted to turn it on, however. Watching "Baraka" on Blu-ray, the image did look a bit sharper and better to my eyes in some scenes with processing engaged, although of course the numerous settings in Manual were a major variable. I need more time to play with it, but after my brief experience yesterday, I'm not yet ready write off Sony's processing on this TV.

Other picture quality factors
While the 4K aspect of the XBR-84X900 may have underwhelmed us, it seemed to be an excellent TV by today's standards. For $25K, I expect nothing less.

Black-level performance measured up to the standards of Sony's other superb high-end LED TVs from 2012, the KDL-HX850 and XBR-HX950 series. The engineers showed us one of our favorite test scenes, Chapter 12 (45 min., 55 sec.) from "Harry Potter and the Deathly Hallows: Part 2," and the XBR-84X900 was clearly superior to the LG and the Sharp. In the shot over Voldemort's army as it prepares to assault Hogwarts, the Sony's backlight got darker and there was significantly more shadow detail and pop. The others looked more washed-out in comparison.

Black-level performance measured up to the standards of Sony's other superb high-end LED TVs from 2012...

There were some issues, however. In one highly contrasting scene where the wizards shoot their wands into the air, both the LG and Sony exhibited a reddish discoloration in the upper black bars as the backlight activated. There was also visible blooming, for example in the letterbox bars during dark scenes that showed some bright material, like the close-up of Voldemort at the beginning of Chapter 12.

Sony also showed us numerous test patterns. One of the more interesting was a full-screen white pattern, where the superior uniformity of the two Sony panels was obvious. The LG in comparison showed backlight variations that were visible in moving material in particular. A Sony engineer told us that the company individually adjusted each XBR-84X900 at the factory to remove as many backlight uniformity imperfections as possible. The backlight wasn't perfect on the two Sonys -- the left-hand corners for example were a bit brighter than the rest of the screen, and a mild blotch of darkness was still discernible on some test patterns -- but for an edge-lit display, the uniformity was excellent.

Sony and LG appear to use identical screen finish. The big 84-inch screen is somewhere between matte and glossy, but it still reflected plenty of ambient light. The Sharp's, in comparison, was fully matte, and should hold up better in bright rooms.

Select measurements
I didn't have time for a full battery of charts and measurements, but I did get the chance to measure black and white levels, grayscale, and color in the Cinema 1 picture setting, the Sony's most accurate. The results were very good but short of perfect.

The most aggressive local-dimming setting, Standard, measured a very dark 2.72 average gamma by default (not unusual with such settings measured with window patterns; and unfortunately I didn't have time to check the other gamma options) but looked fine, with solid shadow detail and no obvious wash-out in brighter scenes. The other two settings, Low and Off, both measured a very good 2.17 gamma. I preferred Standard to the Low or Off dimming, since it delivered the best black level by far (0.0003 footlambert (fL) on a 0 percent pattern, compared with 0.016 for Low; lower luminance for black is better). Maximum light output, if you care, was a searing 140 fL in Vivid mode with a window, and 118 full-screen.

Grayscale was good by default (6618K average at 10 percent to 100 percent, with a 6500K target) and based on past experience with Sony, it should be easily tweakable to near-perfection. The set's color performance was very good albeit not spectacular. Average color error was 3.21, with the worst offender being green at 4.18 (the nominal threshold for human perception is 3). I'd like to see a full color management system on a TV this expensive, allowing a calibrator to correct those errors.

Is 3D a good reason to want 4K?
For most people the answer is "Hell, no." But if we leave aside the lack of 3D content, the distaste many viewers have for 3D, and the fact that you'll have to don glasses, 3D is the best reason to like 4K.

Passive 3D, employed by this Sony and its LG counterpart, is inherently more comfortable and enjoyable to watch than active 3D. Unfortunately, until 4K came along, passive 3D TVs were limited to half the vertical resolution of 1080p (1,920x540 pixels), which caused artifacts and visible line structure in some scenes. The extra pixels of 4K allow the TVs to overcome that limitation, delivering higher than 1080p resolution (3,840x1,080 pixels) per eye.

Sony's new sleeker passive glasses.
Ty Pendlebury/CNET

The XBR-84X900 creates the best 3D image I've seen on a flat-panel TV. Watching my favorite 3D test, "Hugo," I saw all of the benefits of passive and none of those artifacts. Line structure in areas where I'd noticed it before, like the edges of Hugo's face (13:33) and of Isabel's (17:06), was nonexistent. The same went for moving lines I'd seen on other passive sets (typically when the camera moved over a scene that contained a horizontal edge at a shallow angle), like the bowler hat of Uncle Claude (22:41) and the edge of a low wall outside the station (22:09). I didn't note the exact seating distance when line structure did become visible, but even from 5 feet (a sickening distance with 3D on a TV this large), I didn't see any.

Meanwhile, the ghostly double images of cross-talk -- for example, in Hugo's hand as it reached for the mouse (5:01) and the tuning pegs on the guitar (7:49) -- were as absent as I'd expect from any passive set. The image was also plenty bright.

The XBR-84X900 creates the best 3D image I've seen on a flat-panel TV.

Sony includes four pairs of standard 3D glasses as well as two of its new, swoopier variety. I tried the latter and they worked fine, although the smaller frame-less lenses caused some reflections and overall I'd prefer larger lenses at the expense of fashion. The company also throws in two pair of passive glasses designed for use with Dual View multiplayer action.

The speakers are detachable.
Ty Pendlebury/CNET

Big speakers, too
An 84-inch screen, and perhaps the need to further differentiate itself from LG, gave Sony license to mount relatively large speakers to either side of the XBR-84X900 (yes, they are removable). The speakers are housed in an aluminum chassis and feature five drivers in each -- a silk-dome tweeter, two woofers, and two ported "subwoofers." The speakers are angled inward by 10 degrees and are capable of a maximum 50-watt output.

The Sony demonstrated better sound quality than the LG based on the demonstration we were shown, with deeper bass and respectable music replay for a TV. Comparing the two for speech reproduction, the X900 sounded more present, with crisp delineation of syllables while the LG sounded more distant and echoey. That's a direct effect of the speakers being mounted in the bottom or rear of the chassis and firing back instead of facing the viewer.

Watching a bombastic scene from "The Green Hornet," the dedicated sub and tweeter helped to create a more dynamic action soundtrack but the difference wasn't as noticeable as during the simple dialogue scene.

Sony's unique-looking chrome-plated stand is also removable for wall-mounting, and the company says pole mounts are also an option.

Other features
And just in case you were wondering, the XBR-84X900 has all of the other extras found in other high-end 2012 Sony TVs. They include the company's full Smart TV suite with built-in Wi-Fi, the X-media bar interface, and a 240Hz refresh rate with numerous dejudder options. See the XBR-HX950 review for details.

Only two of the four HDMI inputs can accept 4K sources, and then at only 24 or 30 frames per second. You'll have to wait for the next generation of 4K TVs (at least) before you get higher-frame-rate 4K capability, for connection to a computer for example. (Update: Sony announced in September 2013 that all of its 4K TVs will be software upgrade-able to HDMI 2.0, allowing 60 frames per second). Custom installers will appreciate the X900's RS-232 port and compatibility with AMX, Crestron, and Control 4 interfaces.

Meanwhile, owners of the XBR-84X900 are just about the only ones able to watch actual 4K content today. Each such TV sold to a consumer (as opposed to a business) comes with a server loaded with 10 full-length 4K movies and a bunch of shorter 4K content. Sony cooked up an app accessible via an included Tablet S that allows easy access to that content. Sony officially describes the equipment as an open-ended "loan," but hasn't asked for any of it back yet.

In explaining the server, Sony's reps were quick to point out that copy protection was a chief concern. It needs a hardwired connection between itself and a single XBR-84X900 to play the content -- sorry, LG 84LM9600 owners, but it won't work for you. It can connect to the Internet only for software updates. Sony says is in the midst of rolling out an update that includes additional 4K films and videos. That update consists of a BD-ROM disc delivered to each customer, snail mail or Sneakernet style. The customer can choose to do the update him- or herself, or a Sony tech will do so free of charge; $25K apparently buys a lot of white-glove extras.

I found the app easy to use, and it made the content easy to access. I especially appreciated the near-instantaneous response when using the scrub bar on the tablet to jump to a new spot in the film. The films looked great, as expected, but since there's only 10 of them (including "The Amazing Spider-Man," "The Other Guys," "Taxi Driver," "The Bridge on the River Kwai" and, yes, "That's My Boy") chances are good most viewers will quickly exhaust the library. The quality of the movies varied greatly, though. The main thing we noticed about this version of "Taxi Driver" was prevalent noise noise or film grain -- that's totally expected for a movie from the mid-1970s, but it can be distracting for viewers accustomed to the pristine sheen of recent movies like the 2012 version of "Total Recall," which was shot and mastered in native 4K resolution.

Conclusion
For the 0.01-percenters wondering whether they should buy the $25,000 Sony or the $20,000 LG, I can't conclusively pick one over the other based on picture quality. However, the Sony's picture is excellent, and in 2012, Sony's best LED TVs handily outperformed LG's. Sony also provides a couple of neat extras that LG doesn't, starting with actual 4K content.

For the other 99.99 percent, it's a waiting game. A bunch of 4K TVs were announced at CES, but pricing still isn't official. When it is announced, I expect those sets to be significantly more expensive than their 1080p equivalents. From what I've seen here, and what I know about the diminishing returns of higher-resolution in HDTVs, they won't be worth the difference in price. But I look forward to putting that theory to the test once they're released.

About The Author

Section Editor David Katzmaier has reviewed TVs and home entertainment gear at CNET since 2002. He is an ISF certified, NIST trained calibrator and developed CNET's TV test procedure himself. Previously David wrote reviews and features for Sound & Vision magazine and eTown.com. He is known to two people on Twitter as "The Cormac McCarthy of consumer electronics."